A boundary condition decoupled steady-state equivalent model for the simulation of FAIMS ion optical path

This paper proposed a boundary condition decoupled steady-state equivalent model (BCD-SSE Model) for high-field asymmetric waveform ion mobility spectrometry (FAIMS) ion optical path simulation, which successfully incorporated ion diffusion loss and oscillatory loss (dispersion voltage) into the steady-state simulation without altering the actual flow field distribution. The accuracy and efficiency of the model were verified by studying the effects of different dispersion voltage amplitudes, frequencies, duty cycles, and carrier gas flow rates on spectral peak characteristics (position, height, and width). The experimental results show that the spectrum generated by the BCD-SSE Model was in good agreement with the existing general FAIMS simulation model (SIMION/SDS Model). Additionally, the precision of the peak height and full width at half maximum (FWHM) in the FAIMS spectrum using the BCD-SSE Model is 10 times and 3 times greater than that of the traditional steady-state model (SS Model), respectively. Most importantly, compared to the SIMION/SDS Model, the BCD-SSE Model reduced the simulation time from the scale of hundreds of minutes to mere minutes, and it resolved the issue of instability in the simulation results encountered with the SIMION/SDS Model. The proposed method resolved the conflict between simulation accuracy and time consumption, provided a fast and accurate steady-state equivalent simulation method for the analysis of FAIMS ion transport processes and the optimization of ion optical path design.